I found a lovely silver 2001 insight with 60,000 miles and bought it on the spot. I drive 43 miles from my home in Arrowbear (At 6200 feet) to work in Banning, CA (At about 1500 ft.) What is the best strategy to get the best mileage climbing a mountain?
I live in Hesperia and drive to the Riverside area daily. I have found that trying to gain speed on the flatter or downhill sections and coast or decelerate on the steep sections helps but in the end it's still a mountain were going over. That's also a good way to make the traffic behind you mad. The other thing that helps is being as careful as possible (coast and regen as much as possible) going down the hill to increase your overall average mpg. As Insightful Trekker wrote, always watch your mpg readout. I've come to accept I'm never going to get the mileage that this car is capable of but it's still better than everyone else is getting. Enjoy the car.
One thing to consider is running with just a slightly discharged battery, so that when you go downhill you get regenerative braking. If you are too strict about keeping out of the battery then you'll be using the brakes going down, which is worse.
3rd gear, mostly. On a 5-6% grade, that'll keep you around 55-60 mph, maybe more if you can get a running start. Try to minimize assist - it'll probably keep cutting in and out - so that you don't drain the battery before reaching the top. If you do, it will try to charge while you're still climbing.
Downhill you can usually be in regen/fuel cutoff all the way. I get maybe 35-40 mpg going up, 150 (or infinite) going down, so I average around 70-75.
Just got back from San Diego and experienced going from below sea level to 4000 ft on I-8; mostly had lots of power to climb and even got up to 86 going up steep hill (MPh). Anyway did not notice a drop in avg MPG; got 50 with cvt and some A/C for the whole trip. Kept to the speed limit mostly. Overall happy with the sipper on the trip.